Design and Characterization of a CMOS MEMS Capacitive Squeeze-Film Pressure Sensor with High Sensitivity

Abstract

A miniaturized, integrated sensor chip for barometric pressure measurement is desired to be deployed for mobile applications. In this work, a capacitive pressure sensor operated based on the elastic squeeze-film damping effect is implemented in a CMOS (complementary metal oxide semiconductor) process to provide convenient signal transduction and excellent sensitivity. Post-CMOS fabrication of the aluminum/silicon dioxide microstructure is convenient as the sensor operation does not require a sealed reference cavity. Compared to prior CMOS micromachined sensors [1], this work demonstrates a better sensitivity of 5.3 Hz/Pa improved by nearly 7X, and a smaller resonant plate size of $100\times 100\ \mu\mathrm{m}^{2}$ reduced by 4X.